Biomedical subjects

S T Fan

Publications and source records attributed to S T Fan.

At least 217 records · Page 12Linked to original sources

PubMed1992

Choice of palliation for malignant hilar biliary obstruction.

Clinical data from 50 consecutive patients with unresectable hilar tumors situated at or proximal to the common hepatic duct were retrospectively analyzed to aid in the selection of appropriate palliative measures. Thirty-four patients had cholangioenteric bypass (CEB) to either left (28 patients), right (3 patients), or both (3 patients) intrahepatic ductal systems. Sixteen patients had nonoperative drainage (NOD) established either endoscopically (4 patients), percutaneously (9 patients), or using a combined endoscopic-percutaneous approach (3 patients). When compared with patients with CEB, patients with NOD had more frequent medical problems (p less than 0.03) and lower serum albumin levels on admission (p less than 0.03). While comparable postprocedural complications (13 CEB patients versus 4 NOD patients) were observed, patients with NOD had a significantly higher hospital mortality (9 CEB patients versus 9 NOD patients, p less than 0.05). Excluding the 12 patients (6 CEB patients versus 6 NOD patients) who died within 30 days after drainage, the quality of survival of the remaining 38 patients was analyzed with reference to 6 objective parameters. Although patients with NOD had significantly more frequent admissions relating to their catheters (p less than 0.02), there was no qualitative difference in the survival rate between the two groups of patients. For selected high-risk patients with limited life expectancy, NOD should be offered. However, additional prospective studies are required to decide the best choice of palliation for patients who are not at such high risk.

Aged↗

PubMed1992

Subclinical hepatocellular carcinoma in Hong Kong Chinese.

Of the 208 Chinese patients with histologically proven hepatocellular carcinoma (HCC) seen during a 5-year period, 191 patients presented with symptomatic HCC and 17 patients with asymptomatic HCC (subclinical HCC, SCHCC) being picked up by alpha-fetoprotein (AFP) screening. Compared with the patients with symptomatic HCC, patients with SCHCC had a better performance status (p less than 0.01), higher serum albumin levels (p less than 0.05) and lower alkaline phosphatase levels (p less than 0.01). In those patients with symptomatic HCC, 4.7% were operable and only 2 patients had a tumour diameter of less than 5 cm. In contrast, patients with SCHCC had a higher operability rate (76.5%, p less than 0.0001) and all had a tumour of less than 5 cm in diameter (p less than 0.0001). Patients with SCHCC, most of whom had their tumour resected, had a better long-term survival (p less than 0.0001). We conclude that patients with SCHCC picked up by AFP serosurveillance have a better performance status, higher operability and better prognosis.

Actuarial Analysis↗

PubMed1992

[Clinical application of antidromic angiography through external jugular vein].

Antidromic angiography through external jugular vein could show the real appearance, limits and reflux veins of cavernous hemangioma. Pathologic changes in venous system were shown with this method. It is a simple and the best method in diagnosing deep and larger cavernous hemangioma which is hard to treat agent. It plays also a role in differential diagnosis of some cystic mass with intracapsular blood. It is also better than tumor cavity angiography.

Adolescent↗

PubMed1992

Cellular immune and cytokine pathways resulting in tissue factor expression and relevance to septic shock.

Cells of monocyte lineage serve as effector cells in the cellular immune response. In addition, they respond to LPS and cytokines with activation and expression of inflammatory effector gene products similar to those elicited by the antigen driven response. The response to antigen proceeds at the T helper cell level through two independent forms of cellular collaboration, contact and lymphokine. We review the control of expression of the Tissue Factor (TF) gene and the function of the TF protein. The enhanced initiation of transcription of the TF gene appears to require engagement of a 56 bp LPS Response Element, an enhancer that is engaged by both AP-1 type heterodimeric complexes as well as NF kappa B like heterodimeric complexes. Dissociation of NF kappa B from Ig kappa B by cytokine and LPS stimulation, and possibly activated T cells, may represent a common pathway to induction of the TF and other inflammatory genes. Enhancement of expression of TF is observed upon adhesion of Mo to endothelial cells and extracellular matrix proteins, as well as upon engagement of leukocyte integrins. The biological effects that follow from expression of TF by vascular cells have been resolved by analysis of function aided by the use of recombinant full length TF and truncated surface domain of TF. The rules of assembly of the cognate ligands of TF, namely the zymogen plasma factors VII and the serine protease factor VIIa, with the soluble surface domain of TF in free solution, in the presence of phospholipid surfaces and cell surface and of the anchored TF molecule have been described. It is evident that assembly of the surface domain of TF with VIIa to form the binary TF.VIIa complex induces a significant increase in the Kcat of the catalytic domain of VIIa for small peptidyl substrates and more profoundly for protein substrate. This provides substantial evidence for an allosteric effect on the catalytic cleft of VIIa that is imparted by binding to TF, its cognate catalytic cofactor. It is also evident that the TF.VIIa complex is proteolytically active and can activate the zymogen plasma factor X to the serine protease Xa in free solution, inferring that extended substrate recognition by induced structural loci of the TF.VIIa complex are created from either or both proteins to constitute a new recognition structure. It is also evident that association of X with charged phospholipid surfaces enhances the proteolytic activation of this zymogen by increasing recognition and susceptibility of the sessile peptide bond deduced from the markedly decreased Km and increased Kcat.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1992

Surgery for malignant obstructive jaundice: analysis of mortality.

Surgery on patients with malignant obstructive jaundice carries formidable morbidity and mortality rates. Clinical records of 120 consecutive patients who had a serum total bilirubin levels of 100 mumol/L or greater before exploration were analyzed retrospectively to provide guidelines for better management. Although most patients underwent bilienteric bypass to either the extrahepatic (n = 45) or intrahepatic ductal system (n = 28), resection was possible in 32 (26.7%). Complications developed in 42 patients (35%), among whome 12 (10%) required reexploration and 32 (26.7%) died within the same hospitalization. Identification of risk factors associated with hospital deaths after surgery was conducted on 84 of the 120 (group A) patients randomly selected from the entire study period. Based on multivariate analysis, age greater than 65 years, a raised serum aspartate transaminase value greater than 90 IU, and serum urea level greater than 7 mmol/L before surgery were the risk factors selected from 39 different clinical (n = 6), laboratory (n = 26), and operative (n = 7) parameters studied. The predictive value was validated in the remaining 36 patients (group B), and a high-risk patient population had been isolated. Because both serum urea and aspartate transaminase values correlated significantly with the necessity of urgent exploration, aggressive nonoperative treatment should be used to control the emergency. Alternative therapeutic options or perioperative management should be considered for the selected high-risk patients before definitive surgical biliary decompression.

Adult↗

PubMed1991

Acute cholangitis secondary to hepatolithiasis.

In a series of 88 patients with acute cholangitis secondary to hepatolithiasis, 26 (30%) required emergency therapeutic intervention because of septicemic shock (n = 15), persistent fever (n = 8), or spreading peritonitis (n = 3). Analysis was made to define factors that predisposed to failure of conservative treatment and characteristics that could predict the need for emergency biliary decompression. The age, incidence of concomitant medical diseases, previous biliary surgery, positive blood culture, bacterial strains resistant to antibiotics used, and multiplicity of bacterial strains in bile cultures in patients who required emergency intervention were similar to these factors in patients who had elective operations after successful conservative management. The incidence of intrahepatic segmental obstruction by stones or strictures was similar, but many more patients who required emergency intervention had concomitant extrahepatic obstruction due to impacted common ductal stones or strictures. Logistic regression analysis of clinical, hematological, and biochemical data showed that maximum pulse rate within 24 hours of presentation (greater than 100 beats per minute, relative risk, 2.8) and platelet count at the time of admission (less than 150 x 10(9)/L, relative risk, 5.2) were the factors with independent significance in predicting the need for emergency therapeutic procedures. This finding may serve as a guideline for identifying high-risk patients for early intervention.

Adolescent↗

PubMed1991

Peri-operative mortality in hepatic resection.

The operative results of hepatic resections (n = 67) during the past 28 months are reported. Major hepatic resection (lobectomy, extended lobectomy) was performed in 78% of patients with hepatocellular carcinoma (HCC) and in 24% of patients with non-HCC diseases. The overall operative mortality was 10%: 15% for HCC and 0% for non-HCC diseases. The operative mortality in the HCC group occurred exclusively in patients who had undergone right or extended right lobectomy. The operative mortality of right or extended right lobectomy in patients with HCC increased considerably with the presence of cirrhosis (32% vs 0%) and a liver function worse than Child's A (60% vs 17%). In HCC, the incidence of operative mortality (47%) and postoperative hepatic failure (73%) was higher when there had been massive operative blood loss (greater than or equal to 4.0 L) and/or persistent postoperative haemorrhage, compared with 0% and 24% respectively in cases without massive peri-operative bleeding. While postoperative hepatic failure was present in 5 of 7 fatalities, it was not an independent prognostic factor, but was dependent on the presence of massive peri-operative blood loss.

Adolescent↗

PubMed1991

Coupling of the adhesive receptor CD11b/CD18 to functional enhancement of effector macrophage tissue factor response.

Initiation and regulation of localized selective proteolysis is an important effector property of cells of macrophage (Mo) lineage. Among such effector responses is the induced expression of tissue factor (TF) by cells of Mo lineage. In characterizing the regulation of the Mo responses that may influence the magnitude of the effector phase of the cellular immune response, we have identified a role for the cell surface adhesive receptor CD11b/CD18 (Mac-1, CR3) to amplify the induced TF response. Occupancy of CD11b/CD18 by MAb as surrogate ligands does not directly initiate a TF response. In contrast, after either T cell-derived cytokine or LPS as initial signals, engagement of CD11b/CD18 by MAb induces a two- to eight-fold functional enhancement of the TF response in murine and human Mo. This pathway of CD11b/CD18 enhancement of this Mo effector response was also confirmed with recognized ligands for CD11b/CD18 by exposure of Mo to immobilized fibrinogen. A quantitative increase of Mo surface expression of TF was validated by flow cytometry. We suggest that engagement of CD11b/CD18 by complementary ligands including adherence to extracellular matrix, and possibly in antigen-driven TH:Mo collaborative responses, results in the transduction of cellular signals that quantitatively enhance the expression of TF per se and thereby enhance the inflammatory component of Mo mediated response.

Animals↗

PubMed1991

Emergency surgical treatment for nonvariceal bleeding of the upper part of the gastrointestinal tract.

Endoscopic and biochemical data were collected prospectively from 1,530 patients admitted with nonvariceal bleeding of the upper part of the gastrointestinal tract between September 1985 and June 1989. Therapeutic endoscopy was done for 93 patients who underwent emergency surgical treatment for bleeding, subsequently required in 29 patients with seven postoperative fatalities. In contrast, 31 (15.7 per cent) of 198 patients (mortality rate of 9.6 per cent at 30 days) died in the hospital who had undergone emergency operation in whom therapeutic endoscopy had not been performed; data for this latter group is now presented. At admission, a greater likelihood of emergency operation was associated with a systolic blood pressure of 100 millimeters of mercury and endoscopic stigmatas of recent hemorrhage (ESRH) (p less than 0.001). Rebleeding rates for the presence of fresh blood, active spurting and oozing hemorrhage or visible vessel in an ulcer base were 26.5, 28.9 and 35.9 per cent, respectively. Endoscopic stigmatas were thus associated with an increased risk of bleeding (p less than 0.0001) and rebleeding led to a sixfold increase in the mortality rate. Congestive cardiac failure, chronic obstructive airway disease, chronic renal failure and a history of previous malignant disease were each associated with postoperative mortality rates of more than 50 per cent. An increased risk of mortality after emergency operation was related to age (p less than 0.0001), preoperative (p less than 0.002) and total (p less than 0.0001) blood transfusion requirement. Immediate operation after resuscitation and endoscopy was required in 87 patients; 11 deaths (hospital mortality rate of 12.7 per cent and 9.2 per cent at 30 days) occurred in this group compared with 20 fatalities (18.0 per cent) documented in 111 patients (9.9 per cent at 30 days) who underwent surgical treatment for rebleeding. We conclude that age, concomitant medical illness and preoperative and total transfusion requirements are each related to outcome after emergency operations. Such urgent intervention is best avoided if at all possible in patients with severe concomitant medical illness.

Acute Disease↗

PubMed1991

Treatment of hepatolithiasis: improvement of result by a systematic approach.

In previous decades the result of treatment of hepatolithiasis has been unsatisfactory. The incidence of residual stones after surgery might reach 77%. In the past 6 years we adopted a systematic approach comprised of accurate delineation of disease in the liver and biliary tract by direct cholangiography, ultrasonography, and computed tomography; tailored surgical treatment according to the extent of involvement of the liver and biliary tract; access to the intrahepatic ducts through the left duct or round ligament approach when there was difficulty with common bile duct exposure; routine use of flexible choledochoscopy; and application of electrohydraulic lithotripsy for large and impacted stones. Complete stone clearance was achieved in 114 of 127 patients (89.8%). Of those patients who had incomplete stone clearance, only six cases (4.7%) were related to technical failure of postoperative choledochoscopy. The incidence of stone recurrence was 15.8%, the lowest rate so far reported. It was the same regardless of whether a biliary drainage procedure had been performed, but the treatment for recurrent stones was facilitated by previous hepaticocutaneous jejunostomy. Overall the surgical treatment required for stone recurrence was of a lesser magnitude than that in the past.

Adolescent↗

PubMed1991

Percutaneous transhepatic choledochoscopic electrohydraulic lithotripsy for common bile duct stones: experience in four high-risk patients.

Choledochoscopic electrohydraulic lithotripsy was applied through a percutaneous transhepatic approach in four high-risk patients with common bile duct stones that were not extractable by duodenoscopic means. All stones were fragmented and removed from three patients, but one patient died from bronchopneumonia before ductal clearance could be achieved. The procedure was well tolerated, without any complication. The major disadvantage is the multiple maneuvers required and the prolonged hospital stay. Percutaneous transhepatic choledochoscopic electrohydraulic lithotripsy provides a safe and effective alternative for nonoperative treatment of common bile duct stones in high-risk patients when the duodenoscopic approach fails.

Aged↗

PubMed1990

Doxorubicin for unresectable hepatocellular carcinoma. A prospective study on the addition of verapamil.

A prospective study was conducted to assess the safety and efficacy of the addition of oral verapamil to intravenous Adriamycin (doxorubicin) for the management of patients with unresectable hepatocellular carcinoma (HCC). All 28 patients studied had histologically verified disease, and cirrhosis was present in 20 of the 21 patients with adequate tissue sampling. The overall median survival was 57 days. Chemotherapy was terminated in seven patients after one course of treatment. Partial response and complete response were noted in four patients (19%) and one patient (4.8%), respectively, among the 21 patients evaluated. Side effects related to the chemotherapy were present in all patients studied. Death from fulminating sepsis occurred in three of the 13 patients with leukopenia. Symptomatic myocardial dysfunction developed in one patient. The addition of verapamil apparently did not potentiate the tumoricidal effect of systemic Adriamycin on HCC but probably did increase its complications.

Carcinoma, Hepatocellular↗

PubMed1990

Long-term results of resection for large hepatocellular carcinoma: a multivariate analysis of clinicopathological features.

Recurrent or metastatic disease is frequently encountered among patients who have had resection of their primary hepatocellular carcinoma. A retrospective study on 117 patients (104 men, 13 women; mean age +/- standard deviation: 53.8 +/- 12.4 yr) who had hepatectomy for large hepatocellular carcinoma (diameter greater than or equal to 5 cm) was conducted to identify an at-risk population for tumor recurrence. Disease-free survival was correlated with 22 clinical (n = 5), serological (n = 2), gross pathological (n = 3) and histological (n = 12) features of the resected specimens using Cox's multivariate regression analysis. Recurrent hepatocellular carcinoma was detected in 74 patients within a median follow-up period of 13.7 mo. Although 17 patients had extrahepatic disease alone, recurrence was confined to the hepatic remnant in 40 patients. Disease-free survival rates at 1, 3 and 5 yr were 40%, 19% and 12%, respectively. Two of the five histological parameters isolated, negative resection margin (p less than 0.01) and encapsulation (p less than 0.006), were identified as favorable independent prognostic predictors. When patients with positive margins were excluded from the analysis, repeated calculation showed that encapsulation was the only important determinant. From this analysis, detailed histological study of the resected tumor is seen to be the only satisfactory means for assessing long-term prognosis. An aggressive approach is warranted among patients with encapsulated tumors. Even with a clear resection margin, adjuvant treatment should be considered for those patients who have unencapsulated lesions.

Adult↗

PubMed1990

Clonal analysis of CD4+ T helper cell subsets that induce the monocyte procoagulant response.

Monocyte procoagulant inducing factor (MPIF) is a T helper cell-derived cytokine that may play a collaborative role in the expression of cell-mediated immune responses. We have attempted to elucidate whether there is a relationship between MPIF-producing T cell clones and currently proposed subsets of murine T helper cells. A large collection of murine CD4+ T cell clones, both Con A-induced and long-term alloreactive clones, was generated for this study. Four subsets were identified among these T cell clones according to their cytokine secreting profiles: Th0 producing IL-2 and IL-4, Th1 producing IL-2, Th2 producing IL-4, and Tnull, a subset producing neither cytokine. The ability to produce MPIF was found to residue within the Th0 and Th1 subsets regardless of whether the clone was Con A-induced or alloreactive. Neither Th2 clones nor Tnull exhibited significant MPIF activity. In addition, a few instances of transition from Th0 to Th2 were associated with a concomitant loss of MPIF expression. The ability to secrete MPIF after stimulation was heterogeneous among Th0 and Th1 clones and did not correlate with IL-2 production by these clones. Our results that the Th1 subset produces MPIF are consistent with findings that the Th1 subset as well as the cytokine MPIF mediates DTH. Additionally, these results suggest that MPIF-producing Th0 clones may also play a role in cell-mediated immune responses.

Animals↗

PubMed1990

Emergency surgery for severe acute cholangitis. The high-risk patients.

Emergency surgery for patients with severe acute cholangitis carries formidable postoperative morbidity and mortality rates. A retrospective study was conducted on 86 consecutive patients who had exploration for the calculous obstructions to identify the high-risk population to guide better management. Septicemic shock was present in 55 patients before surgery. All patients had ductal exploration under general anesthesia. Additional procedures included cholecystectomy (n = 55), cholecystostomy (n = 5), and transhepatic intubation (n = 2). Complications and deaths occurred in 43 (50%) and 17 (20%) patients, respectively. Multivariate analysis on the 25 clinical (n = 14) and biochemical (n = 11) parameters evaluated yield the following five predictive factors (relative risk): the presence of concomitant medical problems (4.5); pH less than 7.4 (3.5); total bilirubin more than 90 mumol/l (3.1); platelet less than 150 x 10(9)/l (2.9), and serum albumin less than 30 g/L (2.9). In the presence of three or more albumin less than 30 g/L (2.9). In the presence of three or more risk factors, postoperative morbidity and mortality rates were 91% and 55%, respectively, which were significantly higher than those with two or less risk factors (34% and 6%, respectively). As thrombocytopenia developed even with transient hypotension, timely ductal decompression would improve outcome of these patients after surgery. For the high-risk population, application of nonoperative biliary drainage might be considered.

Acute Disease↗

PubMed1990

Bleeding duodenal ulcer. A prospective evaluation of risk factors for rebleeding and death.

There were 12 hospital deaths in 433 patients (2.8%, 1.6% at 30 days) presenting with bleeding duodenal ulcer. Excluding patients who underwent immediate operation or early elective surgery, where ulcer size was measured at initial endoscopy rebleeding was evident in 40/288 patients (13.9%) and was associated with an increased mortality (0.4% v 12.5%) (p less than 0.0001). Rebleeding rates for ulcers less than or equal to 1 cm and greater than 1 cm were respectively 28/239 (11.7%) and 12/49 (24.5%) (p less than 0.02). Rebleeding occurred in 13/186 patients (7.0%) in whom endoscopic stigmata of recent haemorrhage were absent and in 27/102 (26.5%) with such stigmata (p less than 0.0001). The mortality rate for patients without stigmata was 3/186 (1.6%) whilst mortality figures for patients with ulcers less than or equal to 1 cm and greater than 1 cm in size were respectively 0/77 and 3/25 (12.0%) when stigmata were identified. Ulcers greater than 1 cm were more frequent in the greater than 60 year age group, more likely to have stigmata and carried an increased risk of rebleeding and mortality.

Age Factors↗

PubMed1990

Role of computed tomography in the management of recurrent pyogenic cholangitis.

A retrospective analysis was performed to define the indications and usefulness of computed tomography (CT) in the management of 62 patients with recurrent pyogenic cholangitis. When performed in 18 patients in the acute phase for persistent fever inexplicable by ultrasonography and cholangiography, CT scans identified the cause of sepsis to be liver abscesses (n = 7), impacted stones in left lateral segments (n = 3) and right posterior inferior duct (n = 1). When performed in 44 patients during remission, CT scans detected impacted intrahepatic stones as the cause of non-opacification of segmental bile ducts on cholangiograms (n = 15), demonstrated liver volume changes (segmental atrophy, n = 31; hypertrophy, n = 5), differentiated intrahepatic stones from pneumobilia (n = 5) and revealed stones in segregated intrahepatic bile ducts (n = 4). Overall 75.8% of CT scans showed valuable intrahepatic findings which were useful in guiding the appropriate treatment for the intrahepatic pathology. In the others without demonstrable intrahepatic pathology on CT, patients were adequately treated for common bile duct pathology alone. It is recommended that CT should be performed when ultrasonography and cholangiography cannot elucidate the cause of persistent fever, when the cholangiogram shows non-opacification of segmental bile ducts, or fails to demonstrate the cause of recurrent acute cholangitis, particularly in patients who have had previous bilio-enteric drainage procedures.

Adult↗

PubMed1990

Results of surgical resection for hepatocellular carcinoma.

The results of surgical resection in 174 patients with hepatocellular carcinoma was studied. The patients included 147 male and 27 female with a mean age of 54 years. Serum alfa-fetoprotein was elevated in 74% and 67% had liver cirrhosis. The operative morbidity was 46.6% and 30 day mortality was 13.2%. The most common complications were hemorrhage and liver failure. The five and eight year survival rates were 15% and 12% respectively. Long survival of more than ten years was possible after resection of large tumours, even in patients with liver cirrhosis.

Adult↗